In order to determine whether NFκB regulated DNMT1 directly, the firefly luciferase reporter constructs containing DNMT1 promoter with NFκB potential target sites was generated (DNMT1-WT/MT1/MT2) and transfected into GC cells, and we found that the luciferase activity increased significantly in cells co-transfected with CagA and DNMT1-WT or DNMT1-MT2 compared with control cells. The gene discussed is DNMT1; the disease is gastric cancer.